Microstructure and electrochemical properties of boron-doped mesocarbon microbeads

The microstructure and electrochemical properties of pristine and boron-doped mesocarbon microbeads (MCMBs) were comparatively studied by X-ray diffraction, field-emission scanning electron microscopy, Raman spectroscopy, and electrochemical measurements. We examined the correlation between the boron-doping effect and the electrochemical properties of boron-doped MCMBs prepared at different heat-treatment temperatures. It was found that boron doping in MCMBs starts above 1800 degrees C, and then the substitution reaction proceeds with increasing heat-treatment temperature. The effect of boron doping is to accelerate graphitization of MCMBs for heat-treatment temperatures in thr range from 1800 to 2500 degrees C. Electrochemical lithium intercalation takes place at a higher potential in boron-doped MCMBs than in undoped MCMBs. presumably because the substitutional boron acts as an electron acceptor in the MCMBs. (C) 2000 The Electrochemical Society. S0013-4651(99)09-070-9. All rights reserved.